The present invention relates to a projecting lamp for projecting images to create visual and decorative effect, and more particularly to a projecting lamp having a focus control bar adapted to finely adjust focus of the projecting lamp to project clear image.
There are various types of projecting lamps available in the markets, some of which have simple structure while others have complicate structure. These projecting lamps may be used in very wide applications, such as making reports, creating visual and decorative effects, etc.
FIGS. 10A and 10B show a conventional projecting lamp currently available in the market. The projecting lamp includes a hollow cylinder 81 fixedly mounted to a top of a stand 80. An illuminating means capable of emitting intensive light is mounted in a closed rear end of the cylinder 81, and a picture holder 83 holding a projecting picture 82, a locating ring member 84, and a front ring member 86 holding a projecting lens 85 are sequentially mounted in an open front of the cylinder 81 from inner side to outer side. And, two straight rods 8 are rearward extended through the front and the locating ring members 86, 84 to connect their rear ends to the picture holder 83. To use the projecting lamp, the illuminating means is turned on for the same to emit light. The emitted light passes through the projecting picture 82 and the projecting lens 85, so that an image on the projecting picture 82 is projected and magnified on a plane, such as a wall surface.
Since a distance between the projecting lamp and the wall surface varies, it is necessary to adjust a distance between the projecting picture 82 and the projecting lens 85 to project a clear image on the wall surface. In FIG. 10A, the distance between the projecting picture 82 and the lens 85 is large. By pulling the straight rods 8 outward, the distance is shortened, as shown in FIG. 10B. To effect focus control in the conventional projecting lamp, an operator must hold the two straight rods 8 at the same to pull or push them in order to obtain a desired focus. Since there is only a very small adjustable distance between the projecting picture 82 and the lens 85, it is difficult for the operator to apply a suitable magnitude of force on the two straight rods 8 in one direction to obtain the desired focus. It is very possible one movement of the rods 8 would bring the projecting picture 82 to be too close to or too far away from the lens 85. Moreover, only one minor touch or vibration of the projecting lamp would possibly result in undesirable change in the adjusted focus, causing inconvenience in using the projecting lamp.
Further, the above-described focusing structure of the conventional projecting lamp assembled from the projecting picture 82, the lens 85 and the straight rods 8 is fixed in the cylinder 81 through a frictional contact of an inner wall surface of the cylinder 81 with a plurality of leaf springs 841 extended from the lens holder 83 and the locating ring member 84. The leaf springs 841 tend to scrap against and therefore damage the inner wall of the cylinder 81. Moreover, the leaf springs 841 are subject to elastic fatigue after they have been used for a prolonged time and therefore lose their intended function of holding the focusing structure in the cylinder 81.
In the conventional projecting lamp, the cylinder 81 is mounted on a top of a vertical stand 80. It is difficult to adjust the cylinder 81 to different elevation angles and it is impossible to rotate the cylinder 81 in a plane relative to the stand 80 to a desired direction.
Therefore, it is desirable to develop an improved projecting lamp to eliminate the drawbacks existing in the conventional projecting lamps.
A primary object of the present invention is to provide a projecting lamp that includes a projecting structure and a focus control bar that work together to enable easy and fine adjustment of a distance between a projecting picture and a projecting lens of the projecting lamp, and the adjusted focus of the projecting lamp is not subjected to easy change due to vibration or collision.
Another object of the present invention is to provide a projecting lamp having a lamp cylinder that is adjustable in its elevation-angle and angular position.
A further object of the present invention is to provide a projecting lamp that can be quickly disassembled for easy storage or conveyance.